Vehicle exhaust systems direct exhaust gases generated by an internal combustion engine to the external environment. These systems are comprised of various components such as pipes, converters, catalysts, filters, etc. The overall system and/or the components are capable of generating undesirable noise as a result of resonating frequencies. Different approaches have been used to address this issue.
For example, components such as mufflers, resonators, valves, etc., have been incorporated into exhaust systems in an attempt to attenuate certain resonance frequencies generated by the exhaust system. The disadvantage of adding additional components is that it is expensive and increases weight. Further, adding components introduces new sources for noise generation.
Another approach utilizes active noise control (ANC) in an attempt to attenuate the undesirable noise. ANC systems utilize components such as microphones and speakers to generate noise that cancels out the undesirable noise. ANC systems can be complex, very expensive, and can take up significant amounts of packaging space. Further, these systems are not always effective in attenuating wide ranges of resonance frequencies.